Full text of DOI:10.1016/S0040-4039(00)01710-X

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 41 (2000) 9205–9207
Segetoside F a new triterpenoid saponin with inhibition of
luteal cell from the seeds of Vaccaria segetalis
Sheng-min Sang,a,d,† Ai-na Lao,a,* Ying Leng,a Zhi-ping Gu,a Zhong-liang Chen,a
Jun Uzawab and Yasuo Fujimotoc
aInstitute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences,
Shanghai 200031, China
bThe Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-01, Japan
cCollege of Pharmacy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274, Japan
dDepartment of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901-8520, USA
Received 12 September 2000; accepted 28 September 2000
Abstract
A new triterpenoid saponin, named segetoside F, showing strong inhibition of luteal cell activity, has
been isolated from the seeds of Vaccaria segetalis. Its structure has been established by chemical reactions
and spectral analyses. © 2000 Elsevier Science Ltd. All rights reserved.
In previous papers,1–3 we have reported the isolation and structural elucidation of segetoside
A, C–E, G–I from the seeds of Vaccaria segetalis (Neck) Garcke (Caryophllaceae), which is
distributed all over China, except southern China, and used in Chinese folk medicine for
promoting diuresis, activating blood circulation and relieving carbuncles.4 Further investigation
of this seed led to the isolation of a new triterpenoid saponin, named segetoside F (1), which has
the inhibition of luteal cell activity. In this paper we wish to report its structural elucidation and
the inhibition of luteal cells.
The n-butanol fraction from the ethanol extract of the seeds of Vaccaria segetalis was
chromatographed on Diaion HP-20, silica gel and RP-18 silica gel to afford segetoside F (1).
Segetoside F (1), an amorphous solid, has the molecular formula C67H104O32 determined by
positive ion FABMS (at m/z 1444 [M+Na]+) as well as 13C and DEPT NMR data. Its spectral
features and physicochemical properties suggested 1 to be a triterpenoid saponin. Comparison
of the signals from the aglycon moiety in the 13C NMR spectra with those from gypsogenin5
showed that the aglycon of compound 1 was gypsogenin and sugars were bound to the C-3 and
C-28 positions of gypsogenin. The hexasaccharide nature of compound 1 was manifested by its
* Corresponding author. Tel: +86-21-64311833 ext. 316; fax: +86-21-64370269; e-mail: anlao@mail.shcnc.ac.cn
† Current address is Rutgers University.
0040-4039/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4039(00)01710-X

9206
Table 1
1
13C (150 MHz) NMR of compound 1 and H (600 MHz) NMR spectra data for the sugar moieties of 1
(C5D5N) (l in ppm, J in Hz)
Position
lC
38.2t
Position
lC
lH
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Glucuronic acid
1
2
3
4
5
6
6-OMe
Galactose
1
2
3
4
5
6
Fucose
1
2
3
4
5
6
4-OAc; CH3
4-OAc; CꢀO
Arabinose
1
2
3
4
5
25.0t
83.8d
55.0s
48.8d
20.7t
32.5t
40.2s
47.8d
36.3s
23.4t
122.4d
144.1s
42.3s
28.4t
23.7t
47.2s
42.0t
46.4t
30.7s
34.0t
32.3t
209.8d
11.1q
15.8q
17.4q
25.9q
176.4s
33.1q
23.7q
103.5d
82.1d
77.4d
72.6d
76.8d
170.3s
52.1q
4.88 (1H, d, J=7.2)
4.17 (1H, m)
4.22 (1H, m)
4.40 (1H, m)
4.39 (1H, m)
3.71 (3H, s)
106.3
74.5d
74.8d
70.1d
77.1d
62.2ta
5.21 (1H, d, J=8.0)
4.51 (1H, m)
4.11 (1H, m)
4.52 (1H, m)
4.10 (1H, m)
4.50 (2H, m)
94.3d
73.8d
80.9d
73.9d
70.8d
16.5q
20.7q
170.7s
6.00 (1H, d, J=8.0)
4.55 (1H, m)
4.25 (1H, m)
5.78 (1H, m)
3.96 (1H, m)
1.18 (3H, d, J=6.0)
1.96 (3H, s)
111.8d
83.6d
78.0d
85.8d
61.9ta
5.73 (1H, brs)
4.87 (1H, m)
4.80 (1H, m)
4.68 (1H, m)
4.30 (1H, m)
4.16 (1H, m)
Rhamnose
1
2
3
4
5
6
102.1d
71.5d
72.4d
84.9d
68.7d
18.6q
6.01 (1H, S)
4.72 (1H, m)
4.57 (1H, m)
4.28 (1H, m)
4.36 (1H, m)
1.78 (3H, d, J=6.0)
Xylose
1
2
3
4
5
107.5d
76.2d
78.7d
70.5d
67.5t
5.02 (1H, d, J=7.2)
4.00 (1H, m)
4.02 (1H, m)
4.18 (1H, m)
3.51 (1H, t, J=10.0)
4.22 (1H, m)
a Signals may be interchanged.

9207
1H [l 6.01, s; l 6.00, d, J=8.0 Hz; l 5.73, brs; l 5.21, d, J=8.0 Hz; l 5.02, d, J=7.2 Hz; l 4.88,
d, J=7.1 Hz] and 13C [l 111.8, 107.5, 106.3, 103.5, 102.1, 94.3] NMR data, respectively (Table
1). Alkaline hydrolysis of compound 1 followed by acid hydrolysis gave fucose, xylose, arabinose
and rhamnose. On the other hand, acid hydrolysis of 1 gave glucuronic acid, galactose, fucose,
xylose, arabinose and rhamnose, so glucuronic acid and galactose were connected to C3 position
of the aglycone, the other four sugars were connected to C28 position. The identity of the
monosaccharide and the sequence of the oligosaccharide chain were determined by a combination
of DEPT, COSY, HMQC, HMQC-RELAY, HMQC-TOCSY, HMBC-TOCSY and HMBC. In
the light of the assigned 1H and 13CNMR spectra (Table 1), the arabinose sugar unit was identified
as a-arabinofuranose,6 and other sugar units were in pyranose form. The a anomeric configuration
for the rhamnose was judged by its C5 data (l 68.7). The b anomeric configurations for the
3
glucuronic acid, the galactose, the fucose and the xylose were judged from their large JH1,H2
coupling constants (7–8 Hz). The HMBC spectrum showed that C3 with HGluA1, CGluA2 with HGal1
,
C28 with HF1, CF2 with HR1, CF3 with HA1, CR4 with HX1, CGluA6 with Hl3.71(ꢁOCH3), Cl170.7 (CꢀO
of acetyl) with HF4 and Hl2.00 (CH3 of acetyl) have cross peaks. Thus, segetoside F (1) (Fig. 1)
was determined to be 3-O-b-
nosyl-gypsogenin-28-O-b- -xylopyranosyl-(1“4)-a-
anosyl(1“3)]-b- -(4-O-acetyl)-fucopyranoside.
D
-galactopyranosyl(1“2)-b-
D
-(6-O-methyl ester)-glucuronopyra-
-arabinofur-
D
L
-rhamnopyranosyl-(1“2)-[a-
L
D
Figure 1. Structure of segetoside F
Segetalin F exhibited the strong activity of inhibition of luteal cell resulting in 100% at a
concentration of 20 mg/ml, Its IC50 was 12.6 mg/ml. The observation that a saponin like segetoside
F showed inhibition of luteal cell activity is unique.
References
1. Sang, S. M.; Lao, A. N.; Wang, H. C.; et al. Phytochemistry 1998, 48, 569.
2. Sang, S. M.; Lao, A. N.; Wang, H. C.; et al. J. Asian Nat. Prod. Res. 2000, 1, 199.
3. Sang, S. M.; Lao, A. N.; Wang, H. C.; et al. Nat. Prod. Sci. 1998, 4, 268.
4. Jiangsu New Medical College, Zhong-yao-da-ci-dian; Shanghai Science and Technology Publisher, 1986; p. 311.
5. Mahato, S. B.; Kundu, A. P. Phytochemistry 1994, 37, 1517.
6. Yu, D.; Yang, J.; Xie, J. Analytical Chemistry Handbook (NMR Spectrum Analysis); Beijing Chemistry and
Industry Publisher, 1989; p. 824.
.